XVI International Botanical Congess

Ectoine acts as a compatible osmolyte in the moderate halophile Halomonas elongata OUT30018. The ectoine synthesis genes, designated ectA (encoding L-2,4-diaminobutyric acid acetyltransferase), ectB (encoding L-2,4-diaminobutyric acid transaminase), and ectC (encoding L-ectoine synthase), were cloned from OUT30018 strain, placed under the control of the CaMV 35Spromoter, and introduced into cultured tobacco BY2 cells. Transgenic lines showed increased hyperosmotic shock tolerance (>700 mOsm), and maintained higher growth rate than the wild-type line under hyperosmotic conditions (<570 mOsm). These results suggest that ectoine protects plant cells against hyperosmotic stress.